Currently I am using a LCD photo keychain with lcd4linux as a miniature display. It displays weather and temperature information, current title from MPD and a few more things. The lcd4linux setup watches a few files and changes the info displayed when the files change (eg. one file gets updated with the caller's name and number when a phone call comes in, another one contains the most recent email's sender). All this works fine but the display is too small.
Come to think of it, what I am doing is what people usually have as information in their smart phones' lock screens. Now I want to accomplish the same on an analog 3.5" screen.
TL;DR: How can I accomplish a near instant display of event notifications (last email, current (last) caller, temp) without a big framework?